// collectiontopics/MapOps.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// Things you can do with Maps

import onjava.CountMap;

import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

public class MapOps {
    public static void printKeys(Map<Integer, String> map) {
        System.out.print("Size = " + map.size() + ", ");
        System.out.print("Keys: ");
        // Produce a Set of the keys:
        System.out.println(map.keySet());
    }

    public static void test(Map<Integer, String> map) {
        System.out.println(
                map.getClass().getSimpleName());
        map.putAll(new CountMap(25));
        // Map has 'Set' behavior for keys:
        map.putAll(new CountMap(25));
        printKeys(map);
        // Producing a Collection of the values:
        System.out.print("Values: ");
        System.out.println(map.values());
        System.out.println(map);
        System.out.println("map.containsKey(11): " +
                map.containsKey(11));
        System.out.println(
                "map.get(11): " + map.get(11));
        System.out.println("map.containsValue(\"F0\"): "
                + map.containsValue("F0"));
        Integer key = map.keySet().iterator().next();
        System.out.println("First key in map: " + key);
        map.remove(key);
        printKeys(map);
        map.clear();
        System.out.println(
                "map.isEmpty(): " + map.isEmpty());
        map.putAll(new CountMap(25));
        // Operations on the Set change the Map:
        map.keySet().removeAll(map.keySet());
        System.out.println(
                "map.isEmpty(): " + map.isEmpty());
    }

    public static void main(String[] args) {
        test(new HashMap<>());
        test(new TreeMap<>());
        test(new LinkedHashMap<>());
        test(new IdentityHashMap<>());
        test(new ConcurrentHashMap<>());
        test(new WeakHashMap<>());
    }
}
/* Output: (First 11 Lines)
HashMap
Size = 25, Keys: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24]
Values: [A0, B0, C0, D0, E0, F0, G0, H0, I0, J0, K0,
L0, M0, N0, O0, P0, Q0, R0, S0, T0, U0, V0, W0, X0, Y0]
{0=A0, 1=B0, 2=C0, 3=D0, 4=E0, 5=F0, 6=G0, 7=H0, 8=I0,
9=J0, 10=K0, 11=L0, 12=M0, 13=N0, 14=O0, 15=P0, 16=Q0,
17=R0, 18=S0, 19=T0, 20=U0, 21=V0, 22=W0, 23=X0, 24=Y0}
map.containsKey(11): true
map.get(11): L0
map.containsValue("F0"): true
First key in map: 0
Size = 24, Keys: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24]
map.isEmpty(): true
map.isEmpty(): true
                  ...
*/
